MUMBAI: Commuters on the Mumbai Metro One corridor faced delays and overcrowding on Thursday after the operator imposed temporary speed restrictions following rail grinding work.The maintenance exercise, carried out in collaboration with Bangalore Metro, is aimed at improving track quality and ride safety. However, the resulting speed curbs slowed train movement, leading to bunching of services and crowd build-up at stations during peak hours.Officials said the restrictions are a standard safety protocol after such works and will remain in place for a limited period. “These measures are necessary to maintain track integrity and ensure commuter safety,” an official said, adding that efforts are on to minimise inconvenience.